The possibilities are endless. Do you want to redo some landscape? Take a digital camera to your local nursery and snap photos of all of the plants that might work. Then come home and digitally plant them in a image of your garden, all in Photoshop of course. (No watering required!) How about a new built-in bookcase? How many shelves and what kind of spacing? Take a picture of the planned location but include a ruler or something with a known dimension. Now you can use Photoshop to draw in your shelves, changing spacing and so forth, and then take measurements off the winning design (with the ruler as a guide). Take another picture of some books. (You have some, right? After all, you are building bookshelves…) Use this book image to fill up your shelves. (Yes it will look like you have twenty copies of War and Peace but you get the idea.) Check it all out and get it right before you even pull out a sawhorse.